Epigenetics in ovarian cancer: premise, properties, and perspectives.

Malignant ovarian tumors bear the highest mortality rate among all gynecological cancers. Both late tumor diagnosis and tolerance to available chemical therapy increase patient mortality. Therefore, it is both urgent and important to identify biomarkers facilitating early identification and novel agents preventing recurrence. Accumulating evidence demonstrates that epigenetic aberrations (particularly histone modifications) are crucial in tumor initiation and development. Histone acetylation and methylation are respectively regulated by acetyltransferases-deacetylases and methyltransferases-demethylases, both of which are implicated in ovarian cancer pathogenesis. In this review, we summarize the most recent discoveries pertaining to ovarian cancer development arising from the imbalance of histone acetylation and methylation, and provide insight into novel therapeutic interventions for the treatment of ovarian carcinoma

Detection and toxicity evaluation of pyrrolizidine alkaloids in medicinal plants Gynura bicolor and Gynura divaricata collected from different Chinese locations

Two edible plants in Southeast Asia, Gynura bicolor and G.divaricata, are not only known to be nutritive but also useful as medicinal herbs. Previous phytochemical investigation of Gynura species showed the presence of hepatotoxic pyrrolizidine alkaloids (PAs), indicating the toxic risk of using these two plants. The present study was designed to analyze the distribution of PA components and tried to evaluate the preliminary toxicity of these two Gynura species. Eight samples of G.bicolor and G.divaricata from five different Chinese locations were collected and their specific PAs were qualitatively characterized by applying an UPLC/MS/MS spectrometry method. Using a pre-column derivatization HPLC method, the total retronecine ester-type PAs in their alkaloids extracts were quantitatively estimated as well. Finally, their genotoxicity was investigated with an effective high-throughput screening method referred to as Vitotox test and their potential cytotoxicity was tested on HepG2 cells. It was found that different types of PAs were widely present in Gynura species collected from south of China. Among them, no significant genotoxic effects were detected with serial concentrations through the present invitro assay. However, the cytotoxicity assay of Gynura plants collected from Jiangsu displayed weak activity at the concentration of 100mg/ml. It is important to note that this research validates in part the indication that the use of Gynura species requires caution

Simultaneous formation of surface ripples and metallic nanodots induced by phase decomposition and focused ion beam patterning

We report the simultaneous formation of self-assembled surface ripples in Cd2Nb2O7Cd2Nb2O7 pyrochlore caused by focused ion beam (FIB) patterning and uniformly distributed metallic nanodots induced by phase decomposition under ion bombardment. The characteristic wavelength of the surface ripples is controllable from the nm to the sub-μmsub-μm scale. High-density Cd metallic nanoparticles, ∼ 5 nm∼5nm, formed and the distribution of nanoparticles is consistent with the morphological characteristics of the ripple pattern. This approach provides a means of fabricating surface nanostructure with various patterns and a controllable particle size and distribution by combining ion beam-induced phase decomposition with high-precision FIB patterning.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87787/2/093112_1.pd